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Platform trials offer a framework to study multiple interventions in one trial with the opportunity of opening and closing arms. The use of common controls can increase efficiency as compared to individual controls. The need for multiplicity adjustment because of common controls is currently a debate among researchers, pharmaceutical companies, and regulators. The impact of common controls on the type one error in a fixed platform trial, i.e. when all treatments start and end recruitment at the same time, has been discussed in the literature before. We complement these findings by investigating the impact of a common control on the type one error and power in a flexible platform trial, i.e. when one arm joins the platform later. We derived the correlation of test statistics to assess the impact of the overlap and compared the results to a trial with individual controls. Furthermore, we evaluate the power, and the impact of multiplicity adjustment on the power in fixed and flexible platform trials. These methodological considerations are complemented by a regulatory guideline review. With multiple arms, the FWER is inflated when no multiplicity adjustment is applied. However, the FWER inflation is smaller with common controls than with individual controls. Even after multiplicity adjustment, a trial with common controls is often beneficial in terms of sample size and power. However, in some cases, the trial with common controls loses the efficiency gain and it might be advisable to run a separate trial rather than joining a platform trial.
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On June 28, 2018, the Committee for Advanced Therapies and the Committee for Medicinal Products for Human Use adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Yescarta for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma and primary mediastinal large B-cell lymphoma, after two or more lines of systemic therapy. Yescarta, which was designated as an orphan medicinal product and included in the European Medicines Agency's Priority Medicines scheme, was granted an accelerated review timetable. The active substance of Yescarta is axicabtagene ciloleucel, an engineered autologous T-cell immunotherapy product whereby a patient's own T cells are harvested and genetically modified ex vivo by retroviral transduction using a retroviral vector to express a chimeric antigen receptor (CAR) comprising an anti-CD19 single chain variable fragment linked to CD28 costimulatory domain and CD3-zeta signaling domain. The transduced anti-CD19 CAR T cells are expanded ex vivo and infused back into the patient, where they can recognize and eliminate CD19-expressing cells. The benefits of Yescarta as studied in ZUMA-1 phase II (NCT02348216) were an overall response rate per central review of 66% (95% confidence interval, 56%-75%) at a median follow-up of 15.1 months in the intention to treat population and a complete response rate of 47% with a significant duration. The most common adverse events were cytokine release syndrome, neurological adverse events, infections, pyrexia, diarrhea, nausea, hypotension, and fatigue. IMPLICATIONS FOR PRACTICE: Yescarta (axicabtagene ciloleucel) was the first chimeric antigen receptor T-cell therapy to be submitted for evaluation to the European Medicines Agency and admitted into the "priority medicine" scheme; it was granted accelerated assessment on the basis of anticipated clinical benefit in relapsed/refractory diffuse large B-cell lymphoma, a condition of unmet medical need. Indeed, Yescarta showed an overall response rate of 66% and a complete response rate of 47% with a significant duration and a manageable toxicity that compared very favorably with historical controls. Here the analysis of benefits and risks is presented, and specific challenges with this important novel product are highlighted, providing further insights and reflections for future medical research.
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Linfoma de Células B Grandes Difuso , Receptores Quiméricos de Antígenos , Adulto , Antígenos CD19/uso terapéutico , Productos Biológicos , Humanos , Inmunoterapia Adoptiva , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Receptores Quiméricos de Antígenos/genéticaRESUMEN
Adolescent idiopathic scoliosis is a disease of the growing skeleton. The goal in therapy is to decelerate or to prevent progression of the spinal curve. As part of a retrospective study the patient group of the scoliosis surgery from 1995-2016 was analysed according to the inclusion criteria of the Scoliosis research Society (SRS). 159 of 643 of the patients fullfilled the specific criteria. The assessment of effectiveness was based on the progression of the angle of curvature. If it was ≤5° it was judged positively. The therapy in accordance to Cheneau is a full-time bracing orthosis. Data from 159 patients - 136 fem. (85.5%), 23 male (14.5%) was analysed. The average age at the beginning of treatment was 13.3±1.7 years. The average duration was 3.47±1.2 years. The average Cobb-angle before treatment was 28.39°±9.44°. At the completion is was 27.7°±12.34°. Stabilisation of scoliosis (≤5°) was achieved for 136 of the patients (85.5%). The final follow-up showed a progression of the Cobb angel>5° in 23 cases, of which 19 had to undergo secondary surgery. The length of therapy had a positive influence (p=0.057) on the result. Brace treatment constitutes an effective method of therapy at curvatures between 20-40°. Short duration of therapy correlates with a expressively increased risk towards progression (p=0.057). The Cheneau brace treatment constitutes an effective treatment at curvature angles between 20-40°. The risk of progression can be reduced by a timely and correct identification.
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Tirantes , Tratamiento Conservador , Escoliosis/terapia , Adolescente , Niño , Humanos , Masculino , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The global aim of medical ethics committees is to judge the scientific quality and the integrity of the content of medical research projects (studies), thereby assessing the benefit-risk profile. Apart from judging content-related aspects and the legal correctness, the study design and the analysis strategy must also be assessed from a biostatistical point of view. This very sophisticated task is further complicated by the fact that medical research constantly faces new challenges.Within this work, current developments in medical research that directly impact the assessability of ethical proposals will be identified and discussed. The aim is to sensitize researchers to the opportunities and challenges of new developments.The work focusses on the topics of digitalization in the healthcare system and individualized medicine. The authors illustrate some problems resulting from these developments that affect the ethical justification of medical research projects. Problems related to medical as well as biostatistical aspects are presented and their direct implications on the legal justification and ethical and moral conceptual integrity are highlighted.New developments in medical research such as digitalization and individualized medicine offer new perspectives for optimized therapies. These promising developments must be further advanced. A critical view on the so far only poorly investigated consequences of embedding new data sources and study designs must urgently accompany this process. Transparency and clarity in formulating ethical proposals is thereby of utmost importance.
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Investigación Biomédica , Atención a la Salud , Alemania , Proyectos de InvestigaciónRESUMEN
BACKGROUND: Increases in the novel serum marker cystatin C are detectable much earlier in the course of chronic kidney disease (CKD) even when levels of serum creatinine are still in the normal range. A major factor causing a decrease in serum creatinine is increasing age. Patients with CKD are more likely to develop cardiovascular disease (CVD) than a healthy population and to suffer premature deaths from CVD related to CKD. The aim of this study was to investigate whether cystatin C, serum creatinine, and estimated glomerular filtration rate (eGFR) predict cardiovascular mortality in patients admitted to the emergency department (ED) with suspected acute coronary syndromes (ACS). METHODS: In 1,282 patients (mean age 62 ± 15 years, 477 women, 805 men) with suspected ACS, baseline cystatin C concentrations, serum creatinine, and estimated glomerular filtration rate (eGFR) were measured at the ED. Clinical assessment and serial high sensitivity cardiac troponin T (hs-cTnT) measurements were used for the diagnosis of ACS. Seventeen cardiovascular deaths were registered during a median follow-up of 365 days. RESULTS: HRs from univariate Cox regression models for each of the potential biomarkers were 12.02 (95% CI 5.10 - 28.34) for cystatin C, 4.53 (1.75 - 11.70) for serum creatinine, and 0.97 (0.96 - 0.99) for eGFR. All three biomarkers showed a significant association with cardiovascular mortality in univariate analyses. The HRs from a model with all three potential biomarkers were 59.21 (95% CI 9.69 - 361.76) for cystatin C, 0.08 (0.01 - 0.58) for serum creatinine, and 0.98 (0.96 - 1.01) for eGFR. The risk association was significant for ln (cystatin C) and ln (serum creatinine). CONCLUSIONS: Results of this prospective study show that the quantification of renal function using cystatin C is useful for predicting cardiovascular mortality in patients with suspected ACS at the ED.
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Síndrome Coronario Agudo/complicaciones , Enfermedades Cardiovasculares/complicaciones , Cistatina C/análisis , Riñón/fisiología , Síndrome Coronario Agudo/mortalidad , Anciano , Biomarcadores , Enfermedades Cardiovasculares/mortalidad , Creatinina , Servicio de Urgencia en Hospital , Femenino , Tasa de Filtración Glomerular , Humanos , Riñón/fisiopatología , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
PURPOSE: Patients with Duchenne muscular dystrophy (DMD) or spinal muscular atrophy (SMA), both neuromuscular diseases, sustain spinal scoliosis in the course of their disease. To reduce the concomitant major morbidity and to improve their quality of life, patients require surgical spine stabilization. This can lead to complications like respiratory, cardiac or neurological complications or wound healing disorders (WHD). To find out the different complexities and risk factors increasing the chance to develop a WHD, the inpatient database was analyzed. METHODS: We performed a retrospective statistical study. Therefore, we analyzed the inpatient database of 180 patients (142 DMD and 38 SMA patients). The focus was on WHD. To figure out the risk factors leading to WHD, we conducted a logistic regression. RESULTS: Cardiac complications occurred most frequently, followed by pulmonary complications and neurological lesions. Fifty-seven out of 180 patients developed a WHD. In 23 cases the WHD was aseptic, in the other 34 cases dermal organisms, Pseudomonas species and intestinal organisms were responsible. By means of the logistic regression, we were able to identify two more risk factors, in addition to diagnosis and gender, for developing a WHD in our patients: the year of surgery and the direction of pelvic tilt. CONCLUSIONS: Most common complications following scoliosis surgery are respiratory and cardiac complications. WHD is a severe complication that implies a prolonged therapy. Some risk factors for developing WHD could be identified in this analysis. Specifically, these were the date of surgery and the direction of pelvic tilt.
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Atrofia Muscular Espinal/complicaciones , Distrofia Muscular de Duchenne/complicaciones , Escoliosis/etiología , Adolescente , Niño , Femenino , Cardiopatías/etiología , Humanos , Modelos Logísticos , Enfermedades Pulmonares/etiología , Masculino , Calidad de Vida/psicología , Estudios Retrospectivos , Escoliosis/psicología , Escoliosis/cirugía , Fusión Vertebral/efectos adversos , Columna Vertebral/cirugía , Cicatrización de Heridas/fisiologíaRESUMEN
BACKGROUND: When constructing new biomarker or gene signature scores for time-to-event outcomes, the underlying aims are to develop a discrimination model that helps to predict whether patients have a poor or good prognosis and to identify the most influential variables for this task. In practice, this is often done fitting Cox models. Those are, however, not necessarily optimal with respect to the resulting discriminatory power and are based on restrictive assumptions. We present a combined approach to automatically select and fit sparse discrimination models for potentially high-dimensional survival data based on boosting a smooth version of the concordance index (C-index). Due to this objective function, the resulting prediction models are optimal with respect to their ability to discriminate between patients with longer and shorter survival times. The gradient boosting algorithm is combined with the stability selection approach to enhance and control its variable selection properties. RESULTS: The resulting algorithm fits prediction models based on the rankings of the survival times and automatically selects only the most stable predictors. The performance of the approach, which works best for small numbers of informative predictors, is demonstrated in a large scale simulation study: C-index boosting in combination with stability selection is able to identify a small subset of informative predictors from a much larger set of non-informative ones while controlling the per-family error rate. In an application to discover biomarkers for breast cancer patients based on gene expression data, stability selection yielded sparser models and the resulting discriminatory power was higher than with lasso penalized Cox regression models. CONCLUSION: The combination of stability selection and C-index boosting can be used to select small numbers of informative biomarkers and to derive new prediction rules that are optimal with respect to their discriminatory power. Stability selection controls the per-family error rate which makes the new approach also appealing from an inferential point of view, as it provides an alternative to classical hypothesis tests for single predictor effects. Due to the shrinkage and variable selection properties of statistical boosting algorithms, the latter tests are typically unfeasible for prediction models fitted by boosting.
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Modelos Teóricos , Algoritmos , Biomarcadores/metabolismo , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Análisis Discriminante , Femenino , Humanos , Metástasis de la Neoplasia , Pronóstico , Modelos de Riesgos Proporcionales , Análisis de Supervivencia , TranscriptomaRESUMEN
Reproducible research (RR) constitutes the idea that a publication should be accompanied by all relevant material to reproduce the results and findings of a scientific work. Hence, results can be verified and researchers are able to build upon these. Efforts of the Biometrical Journal over the last five years have increased the number of manuscripts which are reproducible by a factor of 4 to almost 50%. Yet, more than half of the code submission could not be executed in the initial review due to missing code, missing data or errors in the code. Careful checks of the submitted code as part of the reviewing process are essential to eliminate these issues and to foster RR. In this article, we reviewed n=56 recent submissions of code and data to identify common reproducibility issues. Based on these findings, guidelines for structuring code submission to the Biometrical Journal have been established to help authors. These guidelines should help researchers to implement RR in general. Together with the code reviews, this supports the mission of the Biometrical Journal in publishing highest quality, novel and relevant papers on statistical methods and their applications in life sciences. Source code and data to reproduce the presented data analyses are available as Supplementary Material on the journal's web page.
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Biometría , Guías como Asunto , Publicaciones Periódicas como Asunto , Estadística como Asunto , Documentación , Reproducibilidad de los Resultados , Programas InformáticosRESUMEN
BACKGROUND: Modern biotechnologies often result in high-dimensional data sets with many more variables than observations (nâªp). These data sets pose new challenges to statistical analysis: Variable selection becomes one of the most important tasks in this setting. Similar challenges arise if in modern data sets from observational studies, e.g., in ecology, where flexible, non-linear models are fitted to high-dimensional data. We assess the recently proposed flexible framework for variable selection called stability selection. By the use of resampling procedures, stability selection adds a finite sample error control to high-dimensional variable selection procedures such as Lasso or boosting. We consider the combination of boosting and stability selection and present results from a detailed simulation study that provide insights into the usefulness of this combination. The interpretation of the used error bounds is elaborated and insights for practical data analysis are given. RESULTS: Stability selection with boosting was able to detect influential predictors in high-dimensional settings while controlling the given error bound in various simulation scenarios. The dependence on various parameters such as the sample size, the number of truly influential variables or tuning parameters of the algorithm was investigated. The results were applied to investigate phenotype measurements in patients with autism spectrum disorders using a log-linear interaction model which was fitted by boosting. Stability selection identified five differentially expressed amino acid pathways. CONCLUSION: Stability selection is implemented in the freely available R package stabs (http://CRAN.R-project.org/package=stabs). It proved to work well in high-dimensional settings with more predictors than observations for both, linear and additive models. The original version of stability selection, which controls the per-family error rate, is quite conservative, though, this is much less the case for its improvement, complementary pairs stability selection. Nevertheless, care should be taken to appropriately specify the error bound.
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Algoritmos , Biomarcadores/análisis , Trastornos Generalizados del Desarrollo Infantil/metabolismo , Reacciones Falso Positivas , Modelos Estadísticos , Estudios de Casos y Controles , Trastornos Generalizados del Desarrollo Infantil/genética , Simulación por Computador , Perfilación de la Expresión Génica , Humanos , Dinámicas no Lineales , FenotipoRESUMEN
SUMMARY: opm is an R package designed to analyse multidimensional OmniLog® phenotype microarray (PM) data. opm provides management, visualization and statistical analysis of PM data, including curve-parameter estimation and discretization, dedicated and customizable plots, metadata management, automated generation of textual and tabular reports, mapping of substrates to databases, batch conversion of files and export to phylogenetic software in the YAML markup language. AVAILABILITY: opm is distributed under the GPL through the Comprehensive R Archive Network (http://cran.r-project.org/package=opm) along with a comprehensive manual and a user-friendly tutorial. Further information may be found at http://www.dsmz.de/research/microorganisms/projects/. CONTACT: johannes.sikorski@dsmz.de.
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Fenotipo , Programas InformáticosRESUMEN
Although platform trials have many benefits, the complexity of these designs may result not only in increased methodological but also regulatory and ethical challenges. These aspects were addressed as part of the IMI project EU Patient-Centric Clinical Trial Platforms (EU-PEARL). We reviewed the available guidelines on platform trials in the European Union and the United States. This is supported and complemented by feedback received from regulatory interactions with the European Medicines Agency and the US Food and Drug Administration. Throughout the project we collected the needs of all relevant stakeholders including ethics committees, regulators, and health technology assessment bodies through active dialog and dedicated stakeholder workshops. Furthermore, we focused on methodological aspects and where applicable identified the corresponding guidance. Learnings from the guideline review, regulatory interactions, and workshops are provided. Based on these, a master protocol template was developed. Issues that still need harmonization or clarification in guidelines or where further methodological research is needed are also presented. These include questions around clinical trial submissions in Europe, the need for multiplicity control across the whole master protocol, the use of non-concurrent controls, and the impact of different randomization schemes. Master protocols are an efficient and patient-centered clinical trial design that can expedite drug development. However, they can also introduce additional operational and regulatory complexities. It is important to understand the different requirements of stakeholders upfront and address them in the trial. While relevant guidance is increasing, early dialog with relevant stakeholders can help to further support such designs.
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Ensayos Clínicos como Asunto , Desarrollo de Medicamentos , Unión Europea , United States Food and Drug Administration , Humanos , Ensayos Clínicos como Asunto/legislación & jurisprudencia , Ensayos Clínicos como Asunto/métodos , Ensayos Clínicos como Asunto/normas , Estados Unidos , Desarrollo de Medicamentos/legislación & jurisprudencia , Desarrollo de Medicamentos/métodos , Proyectos de Investigación , Guías como Asunto , Evaluación de la Tecnología Biomédica/legislación & jurisprudenciaRESUMEN
BACKGROUND: Little is known about the long-term success of non-drug therapies for treating dementia, especially whether the effects are sustained after therapy ends. Here, we examined the effects of a one-year multimodal therapy 10 months after patients completed the therapy. METHODS: This randomised, controlled, single-blind, longitudinal trial involved 61 patients (catamnesis: n = 52) with primary degenerative dementia in five nursing homes in Bavaria, Germany. The highly standardised intervention, MAKS, consisted of motor stimulation, practice of activities of daily living (ADLs), and cognitive stimulation. Each group of 10 patients was treated for 2 h, 6 days a week for 12 months. Control patients received standard nursing home care. At baseline, at the end of therapy (month 12), and 10 months thereafter (month 22), cognitive functioning was assessed using the cognitive subscale of the Alzheimer's Disease Assessment Scale, and the ability to perform ADLs was assessed using the Erlangen Test of Activities of Daily Living. RESULTS: During the therapy phase, the MAKS patients maintained their cognitive function and ability to carry out ADLs. After the end of therapy, both the control and the MAKS groups deteriorated in both their cognitive function (control, p = 0.02; MAKS, p < 0.001) and their ability to carry out ADLs (control, p < 0.001; MAKS, p = 0.001). However, in a confound-adjusted multiple regression model, the ability of the MAKS group to perform ADLs remained significantly higher than that of the control group even 10 months after the end of therapy (H0: ßMAKS + ßMAKS month 22 = 0; χ2 = 3.8568, p = 0.0496). Cohen's d for the difference between the two groups in ADLs and cognitive abilities 10 months after the end of therapy was 0.40 and 0.22, respectively. CONCLUSIONS: A multimodal non-drug therapy of dementia resulted in stabilisation of the ability to perform ADLs, even beyond the end of therapy. To prevent functional decline for as long as possible, therapy should be performed continuously until the benefit for the patient ends. Follow-up studies on larger numbers of patients are needed to definitively confirm these results. TRIAL REGISTRATION: http://www.isrctn.com Identifier: ISRCTN87391496.
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Actividades Cotidianas , Terapia Cognitivo-Conductual/estadística & datos numéricos , Demencia/epidemiología , Demencia/terapia , Anciano , Terapia Combinada/estadística & datos numéricos , Demencia/diagnóstico , Femenino , Estudios de Seguimiento , Alemania/epidemiología , Humanos , Masculino , Prevalencia , Factores de Riesgo , Método Simple Ciego , Resultado del TratamientoRESUMEN
Flexible modeling frameworks for species distribution models based on generalized additive models that allow for smooth, nonlinear effects and interactions are of increasing importance in ecology. Commonly, the flexibility of such smooth function estimates is controlled by means of penalized estimation procedures. However, the actual shape remains unspecified. In many applications, this is not desirable as researchers have a priori assumptions on the shape of the estimated effects, with monotonicity being the most important. Here we demonstrate how monotonicity constraints can be incorporated in a recently proposed flexible framework for species distribution models. Our proposal allows monotonicity constraints to be imposed on smooth effects and on ordinal, categorical variables using an additional asymmetric L2 penalty. Model estimation and variable selection for Red Kite (Milvus milvus) breeding was conducted using the flexible boosting framework implemented in R package mboost.
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Falconiformes/fisiología , Modelos Biológicos , Animales , Demografía , Reproducción , Estaciones del Año , Árboles/clasificaciónRESUMEN
OBJECTIVE: Animal studies suggest pathological foetal programming of hypothalamic circuits regulating food intake in the setting of leptin deficiency and intrauterine growth restriction (IUGR). We aimed to compare placental leptin synthesis and leptin-binding capability in venous cord blood between IUGR newborns and neonates born appropriate for gestational age (AGA). DESIGN: Prospective controlled multicentre study. PATIENTS: Twenty-one ultrasound-proven IUGR and 33 AGA neonates. MEASUREMENTS: The concentration of leptin and soluble leptin receptor (sOB-R) in venous cord blood at birth was determined. Moreover, placental gene and protein expression of leptin and placental mRNA expression of functional and total leptin receptor isoforms were measured. RESULTS: Whereas log-leptin concentration in venous cord blood did not differ between IUGR and AGA newborns, the concentration of log-sOB-R was elevated in IUGR neonates (p(confounder adjusted)=0·009). Placental leptin protein synthesis as well as leptin mRNA was significantly higher in IUGR than in AGA infants (log-transformed, relative gene expression, p(confounder adjusted)=0·004). Analysis of gene expression of functional and total leptin receptor isoforms did not show any difference between both groups. CONCLUSIONS: Leptin-binding capability in venous cord blood is increased in IUGR newborns. Thus, via foetal programming, reduced biologically active leptin levels might contribute to a perturbed regulation of appetite.
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Retardo del Crecimiento Fetal/metabolismo , Leptina/metabolismo , Adolescente , Adulto , Western Blotting , Femenino , Sangre Fetal/metabolismo , Edad Gestacional , Humanos , Recién Nacido , Reacción en Cadena de la Polimerasa , Embarazo , Estudios Prospectivos , Receptores de Leptina/metabolismo , Adulto JovenRESUMEN
OBJECTIVE: To identify the prognostic importance of preceding invasive ventilation, renal replacement therapy, and catecholamine therapy for long-term survivors after surgical critical illness. SUMMARY BACKGROUND DATA: Nothing is known about the effect of preceding intensive care unit (ICU)-related therapies on long-term outcome. METHODS: We performed a retrospective analysis of prospectively collected data of an ICU patient cohort linked to a local database. Adult patients (n = 1462) admitted to a 12-bed ICU between 1993 and 2005, who had an ICU length of stay of more than 4 days, were followed up until the end of the second year after ICU admission. Hazard function was explored by Weibull modeling and likelihood ratio tests. Cox-type structured hazard regression models were used to analyze linear, nonlinear, or time-varying associations of therapeutic variables with 2-year survival time of a patient subgroup, which had survived the period of high hazard. RESULTS: Hazard rate declined exponentially up to day 195 after ICU admission, and became constant thereafter. A total of 808 patients reached this stable stage of their disease forming the study population. Of these patients, 648 (80.2%) were still alive at the end of the second year after ICU admission. Underlying diseases were major determinants for long-term outcome. Long-term mortality was significantly associated with the acute extent of physiological derangement during ICU stay (maximum Apache II score), but was independent from the duration of preceding invasive organ support. CONCLUSION: In surgical patients with a prolonged ICU length of stay, an exorbitant mortality exists for about half a year after ICU admission. Later on, life expectancy of surviving patients is largely determined by the underlying disease and, to a minor degree, by the acute extent of homeostatic disturbance during ICU stay. The duration of preceding invasive therapies does not limit long-term survival.
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Catecolaminas/uso terapéutico , Cuidados Críticos , Enfermedad Crítica/mortalidad , Terapia de Reemplazo Renal , Respiración Artificial , Lesión Renal Aguda/terapia , Humanos , Unidades de Cuidados Intensivos , Pronóstico , Insuficiencia Respiratoria/terapia , Choque/terapia , Tasa de SupervivenciaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Master protocols have received a growing interest during the last years. By assigning patients to specific substudies, they aim at targeting and accelerating clinical development. Given their complexity, basket, umbrella, and platform designs have raised challenging regulatory and statistical questions, especially the control of multiplicity in confirmatory trials. In basket trials, regulatory assessment of the benefit/risk in pooled populations and choice of the treatment indication is challenging. We provide here our perspectives on these topics. In master protocols, as long as the statistical hypotheses tested between the different substudies are independent, no supplementary adjustment for multiplicity over the different substudies should be required. Moreover, sharing a control arm within an umbrella or a platform trial investigating different drugs would not require a correction for the type I error rate, whereas the chance of multiple false positive regulatory decisions should be recognized. In basket trials, pooling across substudies requires a rationale supporting the intended indication and should be preplanned. Assessment of the benefit/risk in pooled target populations can be complicated by differences in design or in efficacy/safety signals between the substudies. While trials governed by a master protocol can offer logistic and financial advantages, more experience is needed to gain a deeper insight into this novel framework.
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Ensayos Clínicos como Asunto/métodos , Interpretación Estadística de Datos , Proyectos de Investigación , Ensayos Clínicos como Asunto/legislación & jurisprudencia , HumanosRESUMEN
Spatial and temporal processes shaping microbial communities are inseparably linked but rarely studied together. By Illumina 16S rRNA sequencing, we monitored soil bacteria in 360 stations on a 100 square meter plot distributed across six intra-annual samplings in a rarely managed, temperate grassland. Using a multi-tiered approach, we tested the extent to which stochastic or deterministic processes influenced the composition of local communities. A combination of phylogenetic turnover analysis and null modeling demonstrated that either homogenization by unlimited stochastic dispersal or scenarios, in which neither stochastic processes nor deterministic forces dominated, explained local assembly processes. Thus, the majority of all sampled communities (82%) was rather homogeneous with no significant changes in abundance-weighted composition. However, we detected strong and uniform taxonomic shifts within just nine samples in early summer. Thus, community snapshots sampled from single points in time or space do not necessarily reflect a representative community state. The potential for change despite the overall homogeneity was further demonstrated when the focus shifted to the rare biosphere. Rare OTU turnover, rather than nestedness, characterized abundance-independent ß-diversity. Accordingly, boosted generalized additive models encompassing spatial, temporal and environmental variables revealed strong and highly diverse effects of space on OTU abundance, even within the same genus. This pure spatial effect increased with decreasing OTU abundance and frequency, whereas soil moisture - the most important environmental variable - had an opposite effect by impacting abundant OTUs more than the rare ones. These results indicate that - despite considerable oscillation in space and time - the abundant and resident OTUs provide a community backbone that supports much higher ß-diversity of a dynamic rare biosphere. Our findings reveal complex interactions among space, time, and environmental filters within bacterial communities in a long-established temperate grassland.
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BACKGROUND AND PURPOSE: This multicenter, phase 3 trial investigates whether the incorporation of concurrent paclitaxel and cisplatin together with a reduced total dose of radiotherapy is superior to standard fluorouracil-cisplatin based CRT. MATERIALS AND METHODS: Patients with SCCHN, stage III-IVB, were randomized to receive paclitaxel/cisplatin (PacCis)-CRT (arm A; paclitaxel 20 mg/m2 on days 2, 5, 8, 11 and 25, 30, 33, 36; cisplatin 20 mg/m2, days 1-4 and 29-32; RT to a total dose of 63.6 Gy) or fluorouracil/cisplatin (CisFU)-CRT (arm B; fluorouracil 600 mg/m2; cisplatin 20 mg/m2, days 1-5 and 29-33; RT: 70.6 Gy). Endpoint was 3-year-disease free survival (3y-DFS). RESULTS: A total of 221 patients were enrolled between 2010 and 2015. With a median follow-up of 3.7 years, 3y-DFS in the CisFU arm and PacCis arm was 58.2% and 48.4%, respectively (HR 0.82, 95% CI 0.56-1.21, p = 0.52). The 3y-OS amounted to 64.6% in the CisFU arm, and to 59.2% in the PacCis arm (HR 0.82, 95% CI 0.54-1.24, p = 0.43). In the subgroup of p16-positive oropharyngeal carcinomas, 3y-DFS and 3y-OS was 84.6% vs 83.9% (p = 0.653), and 92.3% vs. 83.5% (p = 0.76) in arm A and B, respectively. Grade 3-4 hematological toxicities were significantly reduced in arm A (anemia, p = 0.01; leukocytopenia, p = 0.003), whereas grade 3 infections were reduced in arm B (p = 0.01). CONCLUSION: Paclitaxel/cisplatin-CRT with a reduced RT-dose is not superior to standard fluorouracil/cisplatin-CRT. Subgroup analyses indicate that a reduced radiation dose seems to be sufficient for p16+ oropharyngeal cancer or non-smokers. CLINICAL TRIAL INFORMATION: NCT01126216; EudraCT Number 2005-003484-23.
Asunto(s)
Cisplatino , Neoplasias de Cabeza y Cuello , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Quimioradioterapia/efectos adversos , Cisplatino/efectos adversos , Fluorouracilo , Neoplasias de Cabeza y Cuello/terapia , Humanos , Paclitaxel , Estándares de ReferenciaRESUMEN
OBJECTIVE: To evaluate characteristics relevant to diagnosis of JC polyomavirus-associated progressive multifocal leukoencephalopathy (PML), and PML risk stratification in a large national cohort of patients with multiple sclerosis during therapy with natalizumab. METHODS: Analysis of 292 adverse drug reaction forms on suspected cases of PML reported to the German national competent authority until July 2017. Patients not fulfilling PML diagnostic criteria or with insufficient information available were excluded. RESULTS: Of the 142 confirmed patients with PML, 72.3% (95% confidence interval [CI] 64.4%-79.1%) were women, and the median age was 43 years (range 19-69). Of these patients, 7.7% (95% CI 4.3%-13.5%) were clinically asymptomatic at time of PML diagnosis. PML was fatal in 9.1% (95% CI 5.3%-15.1%) of the patients. Infratentorial lesions on imaging were reported in 40% (95% CI 32.0%-48.6%) of the patients. JC polyomavirus DNA in CSF was undetectable at time of first analysis in 23.8% (95% CI 17.3%-31.9%) of the patients. Three patients tested negative for anti-JC polyomavirus antibodies within 6 to 18 months before PML diagnosis, with seroconversion confirmed 5.5 months, 7 months (in a post hoc analysis only), or at time of PML diagnosis. CONCLUSIONS: JC polyomavirus DNA detection in CSF has limited sensitivity in early PML, and clinical and imaging presentation may be atypical. Thus, critical revision of current PML diagnostic criteria is warranted. Negative anti-JC polyomavirus antibodies in sera do not preclude the later development of PML. This emphasizes the need for close and regular serologic, imaging, and clinical monitoring in patients treated with natalizumab.